A general chiller apparatus conventionally has a circuit configuration in which a refrigerant is circulated in each pipe by a refrigerating cycle for cooling and a refrigerant cycle for heating, and a work as a load to be heat-insulated at a local part of the refrigerant cycle is interposed and connected. The refrigerating cycle serves as a primary temperature adjustment circuit of a circuit configuration in which an electric compressor compresses a refrigerant gas and feeds it to a condenser on the delivery side as a high pressure gas, the condenser condenses the high pressure gas and reduces the same through an expansion valve of a pressure reducing mechanism, followed by being fed to an evaporator, and the evaporator evaporates a decompressed refrigerant put in a low-pressure gas-liquid mixed state and allows it to be sucked into the suction side of the compressor, followed by a repetition of the compression again. The refrigerant cycle serves as a secondary temperature adjustment circuit of a circuit configuration in which the evaporator of the refrigerating cycle is used in common and refrigerant liquid put in a low-pressure liquid state is recovered by and stored in a refrigerant tank, and the refrigerant liquid appropriately heated by a heating device (heater) mounted to the refrigerant tank is returned to the evaporator with the work intervened.
A rotational speed of the compressor equipped in the refrigerating cycle hereat and a heating temperature of the heating device equipped in the refrigerant cycle, and a refrigerant flow rate by a pump linked to the refrigerant tank are controlled by a control device provided for use of a selective temperature setting in a predetermined temperature range (−20° C. to 60° C., for example) for a user according to a temperature difference between a setting temperature and a work temperature. The refrigerating cycle and the refrigerant cycle are respectively provided with temperature sensors, and the work temperature is detected from the temperature sensor provided at a spot on the work side more than the pump of the refrigerant cycle.
The control device performs control of operation modes different according to a temperature difference between an initial setting temperature and a work temperature. Since a cooling function of the refrigerating cycle is not required upon a high temperature setting in which there occurs a temperature difference (exceeding 10° C., for example) at which the setting temperature is much higher than the work temperature, for example, an operation mode of suppressing low the rotational speed of the compressor, setting high the heating temperature of the heating device of the refrigerant cycle, and giving priority to a heating function so as to eliminate the temperature difference is executed. Also, since a heating function by the heating device of the refrigerant cycle is not required upon a low temperature setting in which there occurs a temperature difference (exceeding 10° C., for example) at which the setting temperature is much lower than the work temperature, an operation mode of setting high the rotational speed of the compressor of the refrigerating cycle without performing the heating setting of the heating device and giving priority to a cooling function so as to eliminate the temperature difference is performed. Further, upon a heat insulting setting (including where the operation mode of giving priority to the above-described heating function or the operation mode of giving priority to the cooling function is continuously performed to reduce the temperature difference or where no temperature difference occurs initially in advance) in which the temperature difference (5° C. to 10° C., for example) at which the setting temperature is close to the work temperature, an operation mode of executing both of the heating function by the heating device and the cooling function of the refrigerating cycle, specifically, changing the rotational speed of the compressor slightly increasingly or decreasingly from a prescribed value so as to eliminate the temperature difference, or changing the heat to be applied by the heating device slightly increasingly or decreasingly from a prescribed value to carry out both the heating function and the cooling function is performed.
Incidentally, as well-known arts each related to the heat insulating function to the work in such a chiller apparatus, there can be mentioned, for example, a “chiller apparatus” (refer to Patent Literature 1) which can be stably operated over a wide temperature range and is capable of controlling the temperature of a coolant with good accuracy, a “chiller apparatus” (refer to Patent Literature 2) which does not require a large-sized heater and is capable of controlling the temperature of a coolant with good accuracy, etc.